Coil spring with ends adapted for coupling without welding

ABSTRACT

Spring apparatus is provided which includes coil springs having intermediate and end coils suitable for interconnection in order to form a continuous spring which maintains a constant load-deflection characteristic over all intermediate coils unaffected by the joint end coils. This configuration therefore finds particular utility in providing bias without compromise of sealing, electromagnetic shielding and/or conductivity.

This application is a division of application Ser. No. 08/710,196, filedSep. 13,1996 now U.S. Pat. No. 5,709,378.

The present invention generally relates to springs and spring devicesfor providing bias, sealing, electromagnetic shielding and conductivity,and is more particularly directed to joining of coil springs while atthe same time maintaining spring characteristics during deflection,i.e., either radial or axial, compression, of the coils, and extensioncaused by loading of the spring along a central axis throughout.

When spring ends are joined to form a closed spring, such as, forexample, an annulus, a further distinguishing feature of such annularsprings is their suitability for either radial loading, i.e., along aradius of the annular spring, or axial loading, i.e., along an axis ofthe spring annulus.

The joining of the spring ends is a problem that has been addressedthroughout the years but with generally unsatisfactory results. This isprimarily due to the fact that the joined ends of the spring do not havethe same load deflection characteristics as intermediate portions of thespring, thus resulting in a nonuniform biasing, or loading, of partswhich can result in inefficient sealing blockage of electromagneticwaves and nonuniform conductivity.

As specifically pointed out in U.S. Pat. No. 3,190,633, springs areusually formed of tempered steel and therefore many times cannot bejoined at the extreme end by soldering since such joint would be tooweak. Nor can they be joined by brazing or welding, since the heatnecessary for such joining often destroys the temper of the steel.

In an attempt to overcome the problems inherent with welding orsoldering, U.S. Pat. No. 3,190,633 utilizes a coupling in the form of atube for the joining of the spring ends. Unfortunately, this introducesa nonlinearity in the spring size; and further, due to the bulkiness ofthe coupling, uniform load characteristics cannot be obtained throughoutthe spring structure which results in the limitations as hereinabovediscussed.

Further elaboration on the disadvantages of joining the ends of a springby adhesive or a solder includes the time-consuming operation foreffecting the union, and the spring is made less efficient, particularlyif a number of the spring coils are loaded with solder. This latterconfiguration also increases in a nonuniform manner the weight of thespring and contributes significantly to a nonlinearity of the springcharacteristics in the region of the joined ends.

Other known methods of constructing annular devices have been taught inthe art over a great number of years. For example, one known method isto provide on one end of the coiled spring, coils of smaller diameter,while another end includes a diameter consistent with intermediate coilsof the spring. Coupling is accomplished by forcing the reduced diameterend into the other end, such-as set forth in U.S. Pat. Nos. 266,529;3,011,775; and 3,186,701. However, in all of these springs, the outercoils are supported by inner coils which, in the area of the joint,disrupt the load-deflection characteristics of the outer coils.

A further teaching of this type of spring may be found in U.S. Pat. No.3,276,761, in which the end having reduced diameter also has protrudingspring forms for engaging spring convolutions of another end of aspring. Again, the overall configuration of the joint to not enablefreedom of movement of the outer coils during compression.

Alternative teachings of spring joining provide for a spring coil ofconstant diameter with the ends connected by forcing them on to aconnecting member, or plug, which is received and positioned within twoends. In this regard, U.S. Pat. No. 735,731 utilizes a screw, orheadless plug, with screw threads of substantially the same pitch as thecoils of the spring. While this results in an endless helical spring,uniformity of resilience along the helical spring cannot be expected dueto the size of the screw utilized for connecting ends of the spring.

U.S. Pat. No. 1,867,723 discloses a coupling member in the form of acap. U.S. Pat. No. 2,001,835 utilizes a connector formed with aplurality of convolutions of relatively larger diameter for engagementwith a constant diameter coil spring.

Other teachings of the connector member include U.S. Pat. No. 2,778,697,which shows a connector strip provided with a set of semicircularrecesses for accepting coils of both ends of a coiled spring. Avariation of this design is shown in U.S. Pat. No. 3,157,056, in whichthe strip taught in U.S. Pat No. 2,778,697 is replaced by a cylindricalmember having recesses for accepting coil springs.

All of this, of course, obviously interfere with the operation of thespring in the area of the coupling member and therefore do not achieveconsistent spring characteristics which are necessary for both efficientbiasing and sealing.

Other connecting members are shown in U.S. Pat. No. 2,721,091, showing arubber embedded helix; U.S. Pat. No. 2,779,647, which shows a keeperlink arrangement; and U.S. Pat. Nos. 3,359,617 and 4,718,868 which showa spring-connecting member.

As set forth in U.S. Pat. No. 2,991,061, other known methods for joininghelical coils include a hook or loop formed on each end of the coilwhich are connected to form the coil into an annulus and methods whichinclude springs having one or more convolutions at each end which arespaced apart from one another, so they may be connected by beingintertwined together to connect the two ends to form an annular springdevice.

However, all of these methods have serious disadvantages, as pointed outin U.S. Pat. No. 2,991,064, and in none of them is produced an annularspring having ends which are so firmly connected that the spring willwithstand severe vibration and shock without malformation or separationof the ends or excessive extension or unwinding.

Further, the springs have uniform load deflection characteristics due tothe interrupted nature of the spring coupling device utilized.

The present invention overcomes the difficulties of the prior art andprovides an array of coil-joining techniques which are suitable foreither axial-type springs, radial-type springs in which the springutilized can have canted external coils that can be round, elliptical,square or rectangular, or a combination.

SUMMARY OF THE INVENTION

Spring apparatus, in accordance with the present invention, generallyincludes a coil spring having two ends and a plurality of intermediatecoils canted along the centerline of the coil spring with each coilhaving a leading portion disposed at a front angle to a normal line tothe centerline and a trailing portion disposed at a back angle to thenormal line. The intermediate coils may be round, elliptical, square,rectangular or a combination of two or more of the recited shapes.

Importantly, end coils congruent with the plurality of intermediatecoils are disposed at the two ends and include back angle means,defining a trailing portion of at least one end coil, for locking theend coils together. In this instance, the end coil trailing portion ofthe end coil has a back angle different from the intermediate coiltrailing portion back angle. When joined, the resulting continuous coilmay be configured for axial or radial loading.

More particularly, the apparatus in accordance with the presentinvention may include an end coil trailing portion having a decreasingback angle along the length of the end coil. In addition, one of the endcoils may be tapered, or both of the end coils may be tapered.

In one embodiment of the present invention, the end coils are taperedasymmetric to the centerline of the coil spring. In addition, where theintermediate coils are elliptical, they may be tapered along a majorand/or along a minor axis of the coils. In one embodiment of the presentinvention, the end coils are both tapered asymmetric to the centerlineof the coil spring, and in the embodiment where the coil springs areelliptical, the end coils may be elliptical with at least one of thecoils being offset along a major axis thereof.

The spring ends may be held together by a snap action, that can consistof threading, straight push, or a combination twist and push can causethe ends to be locked together or have interference between coils tocause the coils to engage each other by having the end coils round orelliptical. In this instance, the means for causing the end coils tosnap together is an elliptical shape thereof, which causes a portion ofthe elliptical shaped end coil to extend exterior to a circumference ofanother end coil.

In this last embodiment, the intermediate coils and the end coils may beelliptical. Further, the end coils have a coil height, measured along aminor axis thereof, which is substantially smaller than an intermediatecoil height, measured along a minor axis thereof.

The hereinabove recited embodiments, as well as the hereinafter recitedembodiments of the present invention, enable the coupling of the ends ofa spring to form a continuous spring in which the coupling of the endcoils do not inhibit or substantially affect the load-deflectioncharacteristics of the continuous spring in the area of the joint endcoils. This occurs because the joining configuration, namely, thecoupling end portions, do not interfere with the compression orexpansion of the intermediate coils of the spring because of their size,position or both with regard to the intermediate coils.

In another embodiment of the present invention, the end coils may have areduced diameter, i.e., "stepped-down" from the size of the intermediatecoils.

In various embodiments of the present invention, the end coils may havean exterior male, round, elliptical, or offset, and an interior female,round, elliptical, or offset, or alternatively the end stepped-downcoils may have both an exterior male configuration and an exteriorfemale configuration. In these embodiments, as hereinafter described ingreater detail, the end coils may be threaded, snapped on, pushed on, orpushed on in a manner to provide locking action.

Further, a coil in the nature of a hook may be provided for furthersecuring a locking of the end coils together with the hook coil beinginterior to the intermediate coils.

In addition, all of the embodiments of the present invention may befurther combined with an elastomer having either a solid center or ahollow center in order to provide sealing, shielding, added force, orenhancing the conductivity by enabling portions of the coil to be bareto enable enhanced conductivity.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will be betterunderstood by the following description when considered in conjunctionwith the accompanying drawings in which:

FIG. 1 is a cutaway side view of one embodiment of the presentinvention, generally showing coupling of two end coils to form acontinuous coil spring;

FIG. 2 is a top view of an end coil corresponding to FIG. 1, prior toassembly;

FIG. 3 is a top view of another end coil according to FIG. 1, prior toassembly;

FIG. 4 is a side view of the end coil shown in FIG. 2;

FIG. 5 is a side view of the end coil shown in FIG. 3;

FIG. 6 is a view of the coil spring shown in FIG. 1, taken along theline 6--6;

FIG. 7 is a view of the coil spring shown in FIG. 1, taken along theline 7--7;

FIG. 8 is a view of the coil spring in FIG. 1, taken along the line8--8;

FIG. 9 is a cutaway side view of an assembled coil spring in accordancewith another embodiment of the present invention;

FIG. 10 is a top view of one end coil of the assembly shown in FIG. 9;

FIG. 11 is a top view of another end coil of the assembly shown in FIG.9, specifically showing portions of elliptical coils thereof for causingthe locking action;

FIG. 12 is a side view of the end coil shown in FIG. 10;

FIG. 13 is a side view of the end coil shown in FIG. 11;

FIG. 14 is a view of the assembly shown in FIG. 9, taken along the line14--14;

FIG. 15 is a view of the assembly shown in FIG. 9, taken along the line15--15;

FIG. 16 is a view of the assembly shown in FIG. 9, taken along the line16--16;

FIG. 17 is a cutaway side view of a spring assembly in accordance withyet another embodiment of the present invention;

FIG. 18 is a top view of an end coil of the assembly shown in FIG. 17;

FIG. 19 is a top view of another end coil of the assembly shown in FIG.17, showing protruding elliptical coils which provide for back anglelocking;

FIG. 20 is a side view of the end coil shown in FIG. 18;

FIG. 21 is a side view of the end coil shown in FIG. 19;

FIG. 22 is a view of the assembly shown in FIG. 17, taken along the line22--22;

FIG. 23 is a view of the assembly shown in FIG. 13, taken along the line23--23;

FIG. 24 is a view of the assembly shown in FIG. 17, taken along the line24--24;

FIG. 25 is a cutaway side view of an assembled coil spring in accordancewith yet another embodiment of the present invention;

FIG. 26 is a top view of an end coil of the assembly shown in FIG. 25;

FIG. 27 is a top view of another end coil shown in FIG. 25;

FIG. 28 is a side view of the end coil shown in FIG. 26;

FIG. 29 is a side view of the end coil shown in FIG. 27;

FIG. 30 is a view of the spring assembly shown in FIG. 25, taken alongthe line 30--30;

FIG. 31 is a view of the assembly shown in FIG. 25, taken along the line31--31;

FIG. 32 is a view of the assembly shown in FIG. 25, taken along the line32--32;

FIG. 33 is a view of the assembly shown in shown in FIG. 25, taken alongthe line 33--33;

FIG. 34 is a cutaway side view of an assembled coil springconfiguration, in accordance with still another embodiment of thepresent invention;

FIG. 35 is a top view of an end coil of the assembly shown in FIG. 34;

FIG. 36 is a top view of another end coil of the assembly shown in FIG.34;

FIG. 37 is a side view of the end coil shown in FIG. 35;

FIG. 38 is a side view of the end coil shown in FIG. 36;

FIG. 39 is a view of the assembly shown in FIG. 34, taken along the line39--39;

FIG. 40 is a view of the assembly shown in FIG. 34, taken along the line40--40;

FIG. 41 is a view of the assembly shown in FIG. 34, taken along the line41--41;

FIG. 42 is a top view of an assembled spring apparatus, in accordancewith another embodiment of the present invention;

FIG. 43 is a cutaway side view of the assembly shown in FIG. 42;

FIG. 44 is a top view of one end coil of the assembly shown in FIG. 42;

FIG. 45 is a top view of another end coil of the assembly shown in FIG.42;

FIG. 46 is a side view of the end coil shown in FIG. 44;

FIG. 47 is a side view of the end coil shown in FIG. 45;

FIG. 48 is a view of the assembly shown in FIG. 43 taken along the line48--48;

FIG. 49 is a view of the assembly shown in FIG. 43, taken along the line49--49;

FIG. 50 is a view of the assembly shown in FIG. 43, taken along the line50--50;

FIG. 51 is a top view of another spring assembly, in accordance withstill another embodiment of the present invention;

FIG. 52 is a cutaway side view of the assembly shown in FIG. 51;

FIG. 53 is a top view of one end coil of the assembly shown in FIG. 52;

FIG. 54 is a top view of another coil of the assembly shown in FIG. 52;

FIG. 55 is a side view of the end coil shown in FIG. 53;

FIG. 56 is a side view of the end coil shown in FIG. 54;

FIG. 57 is a view of the assembly shown in FIG. 52, taken along the line57--57;

FIG. 58 is a view of the assembly shown in FIG. 52, taken along the line58--58;

FIG. 59 is a view of the assembly shown in FIG. 52, taken along the line59--59;

FIG. 60 is a cutaway side view of a spring assembly, in accordance withthe present invention utilizing a circular canted spring with anelliptical snap-on coupling;

FIG. 61 is a view of the assembly shown in FIG. 60, taken along the line61--61;

FIG. 62 is a cutaway side view of a spring assembly, in accordance withthe present invention, wherein the intermediate coils are square, andthe end coils are elliptical;

FIG. 63 is a view of the spring assembly shown in FIG. 62, taken alongthe line 63--63;

FIG. 64 is a cutaway side view of a spring assembly, utilizingrectangular intermediate coils and circular end coils;

FIG. 65 is a view of the spring assembly shown in FIG. 64, taken alongthe line 65--65;

FIG. 66 is a cutaway side view of a spring assembly, utilizing circularintermediate coils with circular canted end coils for snap-onengagement;

FIG. 67 is a view of the spring assembly shown in FIG. 66, taken alongthe line 67--67;

FIG. 68 is a cutaway side view of a spring assembly, utilizingelliptical canted intermediate coils and elliptical end coils;

FIG. 69 is a view of the spring assembly shown in FIG. 68, taken alongthe line 69--69;

FIG. 70 is a cutaway side view of an assembly of an embodiment of thepresent invention similar to that shown in FIG. 68;

FIG. 71 is a view of the spring assembly shown in FIG. 70, taken alongthe line 71--71;

FIG. 72 is a top view of another embodiment of the present inventionutilizing male and female end coils;

FIG. 73 is a side view of an end coil of the spring assembly shown inFIG. 72 in which the end coils are abutting;

FIG. 74 is a side view of another end coil of the spring assembly shownin FIG. 72 in which the female end coils is disposed within theintermediate coils;

FIG. 75 is a view of the end coil shown in FIG. 73, taken along the line75--75;

FIG. 76 is a view of the end coil shown in FIG. 74, taken along the line76--76;

FIG. 77 is a top view of a spring assembly similar to that shown in FIG.72 in which the end coils are spaced apart;

FIG. 78 is a side view of an end coil of the spring assembly shown inFIG. 77;

FIG. 79 is a side view of another end coil of the spring assembly shownin FIG. 77;

FIG. 80 is a top view of another spring assembly similar to that shownin FIG. 77 in which one end coil is tapered;

FIG. 81 is a side view of an end coil of the spring assembly shown inFIG. 80;

FIG. 82 is a side view of another end coil of the spring assembly shownin FIG. 80;

FIG. 83 is a top view of a spring assembly in which the end coilsinclude abutting tapered coils;

FIG. 84 is a side view of an end coil of the spring assembly shown inFIG. 83;

FIG. 85 is a side view of another end coil of the spring assembly shownin FIG. 83;

FIG. 86 is a spring assembly similar to that shown in FIG. 83 withseparate tapered end coils;

FIG. 87 is a side view of an end coil of the spring assembly shown inFIG. 86;

FIG. 88 is a side view of another end coil of the spring assembly shownin FIG. 86;

FIGS. 89a and 89b are side views of a spring assembly similar to FIG. 77in which the intermediate coils are rectangular and the one end coil ismale, having exterior spaced apart coils;

FIGS. 90a and 90b show a female end coil disposed within intermediatecoils for coupling with the end coils shown in FIGS. 89a and 89b;

FIG. 91 is a side view of a spring assembly formed by coupling of theend coils shown in FIGS. 89a and 90b;

FIG. 92 is a top view of an alternative embodiment of the springassembly, in accordance with the present invention, utilizing two endcoils and an insert coil;

FIG. 93 is a side view of the spring assembly shown in FIG. 92;

FIG. 94 is a partially cutaway side view of the coil assembly shown inFIG. 92 when fully assembled;

FIG. 95 is a view of the spring assembly shown in FIG. 93 taken alongthe line 95--95;

FIG. 96 is a view of the spring assembly shown in FIG. 93 taken alongthe line 96--96;

FIG. 97 is a top view of an alternative embodiment of the presentinvention, similar to FIG. 77, in which both the male and female endcoils are exterior to the intermediate coils;

FIG. 98 is a side view of an end coil of the spring assembly shown inFIG. 97;

FIG. 99 is a side view of another end coil of the spring assembly shownin FIG. 98 in which the female end coil is exterior to the intermediatecoils;

FIG. 100 is a view of the end coils shown in FIG. 98 taken along theline 100--100;

FIG. 101 is a view of the end coil shown in FIG. 99 taken along the line101--101;

FIG. 102 is a cutaway side view of the spring assembly shown in FIG. 97at maximum deflection, illustrating independence of the deflection ofthe intermediate coils from the coupling end coils;

FIG. 103 is a top view of still another embodiment of the presentinvention, utilizing triangular end coils;

FIG. 104 is a side view of one end coil of the spring assembly shown inFIG. 103;

FIG. 105 is a side view of another end coil of the spring assembly shownin FIG. 103;

FIG. 106 is a view of the end coil shown in FIG. 104 taken along theline 106--106;

FIG. 107 is a view of the end coil shown in FIG. 105 taken along theline 107--107;

FIG. 108 is a cutaway side view of the spring assembly shown in FIG. 103at maximum deflection;

FIG. 109 is a top view of yet another embodiment of the presentinvention similar to the assembly shown in FIG. 103;

FIG. 110 is a side view of an end coil of the spring assembly shown inFIG. 109;

FIG. 111 is a side view of another end coil of the spring assembly shownin FIG. 109;

FIG. 112 is a view of the end coil shown in FIG. 110 taken along theline 112--112;

FIG. 113 is a cutaway side view of the spring assembly 109 at maximumdeflection under a load (not shown);

FIG. 114 is a view of the end coil shown in FIG. 111 taken along theline 114--114;

FIG. 115 is a view of the end coil shown in FIG. 111 taken along theline 115--115;

FIG. 116 is a top view of a spring assembly, in accordance with thepresent invention, utilizing an end locking system with a male hookstem;

FIG. 117 is a side view of a male end coil of the spring assembly shownin FIG. 116 showing a male hook stem with a bent latch and abuttingcoils;

FIG. 118 is a side view of a female end coil of the spring assemblyshown in FIG. 116 having round centered coil abutting coils;

FIG. 119 is a view of the end coil shown in FIG. 117 taken along theline 119--119;

FIG. 120 is a view of the end coil shown in FIG. 118 taken along theline 120--120;

FIG. 121 is a cutaway side view of the spring assembly shown in FIG. 116at maximum deflection and illustrating the coupled end coils not beingin interference with the deflection of the intermediate coils uponloading;

FIG. 122 is a side view of a spring assembly, in accordance with thepresent invention, further including an elastomer surrounding theintermediate and end coils;

FIG. 123 is a view of the spring assembly shown in FIG. 122 taken alongthe line A--A in one embodiment in which the elastomer has a solidcenter;

FIG. 124 is a view of the spring assembly shown in FIG. 122 taken alongthe line A--A in which the elastomer has a hollow center;

FIG. 125 is a view of the spring assembly shown in FIG. 122 taken alongthe line B--B in which the elastomer has a solid center;

FIG. 126 is a view of the spring assembly shown in FIG. 122 taken alongthe line B--B in which the elastomer has a hollow center;

FIG. 127 is a view of the spring assembly shown in FIG. 122 taken alongthe line C--C in which the elastomer has a solid center;

FIG. 128 is a view of the spring assembly shown in FIG. 122 taken alongthe line C--C in which the elastomer has a hollow center;

FIG. 129 is a view of the spring assembly shown in FIG. 122 taken alongthe line D--D in which the elastomer has a solid center;

FIG. 130 is a view of the spring assembly shown in FIG. 122 taken alongthe line D--D in which the elastomer has a hollow center;

FIG. 131 is a side view of uncanted, circular intermediate and endcoils;

FIG. 132 is an end view of the coils shown in FIG. 131;

FIG. 133 is a side view of mating uncanted, circular intermediate andend coils;

FIG. 134 is an end view of the coil shown in FIG. 133; and

FIG. 135 is a side view of an assembled, uncanted circular coil coilspring.

DETAILED DESCRIPTION

It should be appreciated that the drawings include specific springangles and in many cases, dimensions and the specific references are setforth by way of example only and are not be construed as limiting in anyway the breadth of the present invention. The specific dimensions areprovided for reference and not repeated in the specification for thesake of clarity.

Turning now to FIGS. 1-3, there is shown spring apparatus 10 whichincludes a coil spring 12 having a plurality of intermediate coils 14,16 canted along a centerline 18 of coil spring 12.

As more clearly shown in FIGS. 4 and 5, each coil 12, 14 includes aleading portion 22, 24 disposed at a front angle 26, 28 along a normalline 30 to the centerline 18. As shown in FIGS. 4 and 5, theseintermediate coils have a front angle, for example purposes only, of30°. Each of the intermediate coils 12, 14 has a trailing portion 34, 36disposed at a back angle 40, 42 to the normal line 30.

As most clearly shown in FIGS. 2-5, end coils 46, 48 of the springapparatus are congruent, or continuous, with the plurality ofintermediate coils 12, 14 and are-disposed at ends 52, 54 of theintermediate coils 12, 14. As shown in FIGS. 4 and 5, each of the endcoils, 46, 48 include trailing portions 58, 60 disposed at back angles62, 64 which are different from the back angles 40, 42 of theintermediate coils.

Alternatively, the back angles 40, 42 may be the same and the frontangles 26, 28, different from one another.

This difference in back angles enables the end coils 46, 48 to bethreaded to one another in a clockwise manner illustrated by the arrow68 in FIG. 1 when the end coil 48 is assembled into the end coil 46 inthe direction of the arrow 70, as shown in FIG. 1.

More particularly, as shown in FIGS. 4 and 5, the end coil trailingportions 58, 60 have a decreasing back angle along a length of the endcoil measured along a centerline 18.

As also illustrated in FIGS. 1-5, one or more of the end coils 46, 48may be tapered, and as is most easily seen in FIGS. 4 and 5, the endcoils may be tapered asymmetrically to the centerline 18. Thus, the endcoils 46, 48 may be threaded, and the tapered ends, along with thedifference back angle, provide a friction interference.

As more clearly shown in FIGS. 6, 7 and 8, the intermediate and endcoils may be elliptical in which there is a touching or interferencebetween the end coils all around the periphery, as indicated by theshading 72. FIGS. 6, 7 and 8 show respectively a first coil 78 on theend coil 46, a second coil 80 on the end coil 46, and a third coil 82 onthe end coil.

Because of the tapered nature of the end coils 46, 48, the height of theintermediate coils 14, 16 enable compression of the spring assembly 10as indicated by the arrows 86 in FIG. 1 without interference from theend coils 46, 48, thus maintaining the load deflection characteristicsof the intermediate coils 14, 16 across the union thereof provided bythe end coils 46, 48.

Turning now to FIG. 9, there is shown another embodiment 90 of thepresent invention, having intermediate coils 92, 94 with end coils 96,98 as more clearly set forth in FIGS. 10-13. As most clearly shown inFIGS. 14-16, end coils 100, 102 are elliptical. As shown in FIG. 11, atleast one end coil 106 is offset in order to provide a three-area pointcontact, or locking point for reducing the deflection load of the spring90 in the area of the coupled end coils 96, 98. As shown in FIG. 9, thethree areas are locking points, upper locking point 108; a lower backangle, locking point 110; and a lower front angle, locking point 112(see also FIGS. 14-16). These locking points are achieved when the endcoil 102 is threaded into the end coil 100 in the direction of thearrows 114, 116, as shown in FIG. 9. The assembly is further facilitatedby the tapered end coils 98 as indicated by the lead lines 120 shown inFIG. 9.

Turning now to FIGS. 17-24, there is shown yet another embodiment 124 ofthe present invention similar to that shown in FIGS. 9-16, whichincludes intermediate coils 126, 128 and end coils 130, 132 with the endcoil 132 tapered, as indicated by the arrow 134 shown in FIG. 17.Individual offset coils 138, 140, 142, 144, most clearly seen in FIG.19, provide six locking areas or points which are staggered axially, thepoints being illustrated at points 148, shown in FIG. 21. The contactpoints are further illustrated in FIGS. 22--24. As hereinabove describedin connection with the embodiment 90, the contact points occur onassembly of the end coil 132 into the end coil 130 by clockwiserotation, indicated by the arrows 150 in FIG. 17, as the end coil 132couples into the end coil 130, as shown by the arrow 152 in FIG. 17.

The staggered contact area arrangement enables compression of the springassembly without significant change in its load deflectioncharacteristics in the area of the coupling end coils 130, 132.

Turning now to FIG. 25, there is shown yet another embodiment 156 of thepresent invention, with the intermediate coils 158, 160, 162, 164 (seeFIGS. 26 and 27). This embodiment features an end coil 164 having asmaller coil height than the coil height of the intermediate coils 160to permit greater deflection of the intermediate canted coils 160 alonga minor axis, that is, the end coil 164 is "stepped down" from theintermediate coil 160. It should be appreciated that, while the coilsare shown as having a right-hand thread, they may also be formed with aleft-hand thread.

As illustrated in FIGS. 30-33, contact locking area is along the majoraxis 164 due to the protruding configuration of individual end coils166, 168 (see FIG. 27).

It is to be appreciated that the end coils 162 have a diameterequivalent to the intermediate coils 158, as shown in FIG. 26, whileonly the end coils 164 have a smaller, or step down, diameter, as shownin FIG. 29. As hereinbefore discussed, variable back angles, asillustrated on the diagram, create interference and the locking gripbetween the end coils, as illustrated in FIGS. 30-33. This unlockingoccurs when the end coils 162, 164 are assembled by a clockwise winding,as indicated by the arrow 172, as shown in FIG. 25, as the end coil 164is inserted into the end coil 162 in the direction of the arrow 174,also shown in FIG. 25. This assembly is suitable for end coils which arewound in a counterclockwise direction, as indicated by the arrows 176 inFIGS. 30-33.

It should be apparent that due to the reduced diameter of the end coils164, deflection of the spring assembly embodiment 156, as indicated bythe arrows 176 along the minor axis 180 (see FIGS. 30-33), is possiblewithout significant change in the load deflection characteristics of thespring assembly 156 in the area of the coupled end coils 162, 164. Thisembodiment is particularly suitable when deflection of the end coils158, 160 along the minor axis 180 is desired with threading locking. Thedeflection of the coils at the locking ends result in higher force andgreater range of deflection of the intermediate coils 160, withoutsubstantial change.

Yet another embodiment 186 of the present invention is shown in FIGS.34-41, which includes intermediate coils 188, 190 and end coils 192,194.

As shown in FIG. 35 and as most clearly evident in FIG. 39, the endcoils 192 include at least one individual round coil 196 to provide adeflection stop; and an elliptical locking coil 198 is extended from theintermediate coils 190 with variable back angles 200, 202 (see FIG. 38).To create interference, there is a reverse locking grip between the endcoils.

The deflection stop occurs when the intermediate coils are compresseddown to the diameter of the round coils in the direction of arrow 204,as shown in FIG. 34. In this embodiment, the end coils 194 are taperedasymmetric to the centerline 206 to the intermediate coils 188, 190 andspring assembly 186. Locking is provided by engagement areas 208, 210,as shown in FIG. 40, provided by the coil 198 contact with intermediatecoil 186 (see FIG. 40). Again, assembly is accomplished by rotating theend coil 194 into the end coil 192 as indicated by the arrow 212 in FIG.34, causing engagement of the end coil 194 into the end coil 192 in thedirection of arrow 214. In this embodiment, a locking end 215, end coil191 provides a stop as indicated by position 214 in FIGS. 34 and 41 bycontact with a first individual end coil 216, four coils wound in acounterclockwise manner, as indicated by the arrow 222 in FIGS. 39-41.Thus, the spring assembly 186 is assembled by threading the end coils192, 194 together until positive stop is encountered.

Turning now to FIGS. 42-50, there is shown an alternative embodiment 220of the spring assembly, or apparatus, wherein intermediate coils 222,224 and end coils 226, 228 are canted along a centerline 230 with eachintermediate coil 224 having a leading portion 234 disposed at a frontangle 236 to a normal line 238 and a trailing portion 242 disposed at aback angle 234 to the normal line 238. Preferably, the intermediatecoils 222, 224 and end coils 226, 228 are elliptical, and an ellipticalshape of at least one individual end coil 248 includes extended portions250, 252 (see FIG. 45) for causing the end coils 226, 228 to snaptogether with the portions 250, 252 extending exterior to thecircumference of end coils 226.

Referring specifically to FIGS. 49 and 50, this provides for engagementbetween the end coils at alternate selected points 260, 262.

Yet another embodiment 266 of the present invention is shown in FIGS.51-59, which includes intermediate coils 266, 268 and end coils 270,272.

This embodiment 266 is similar to embodiment 220, shown in FIGS. 42-50,except that two individual end coils 276, 278 have a coil heightmeasured along a minor axis 280 (see FIGS. 57-59) which is substantiallysmaller than an intermediate coil height measured along the minor axis.This provides for four contact areas 282, 284, 286, 288, as shown inFIGS. 57-59.

Another distinguishing difference between the embodiments 220, 266 isthat the location of the leading end coil 292 of the spring apparatus220 has an end 294, as shown in FIGS. 45 and 48, which is disposed in alower left quadrant (see FIG. 48) whereas a leading end coil 300 of thespring apparatus 266 has an end 302 disposed in an upper right quadrant,as shown in FIGS. 54 and 57.

Also, as shown in FIGS. 50 and 59, the end coils 226, 270, respectively,provide positive stops upon assembly, the position of which is indicatedat 306 and 308, respectively, in FIGS. 50 and 59.

Alternative embodiments 310, 312, 314, 316, 318 and 320, in accordancewith the present invention, are shown respectively in FIGS. 60-71.

As shown in FIGS. 60 and 61, embodiment 310 includes circularintermediate coils 322 with elliptical end coils 324. The embodiment 312in FIGS. 62 and 63 includes square intermediate coils 326 and ellipticalsnap-on end coils 328.

The embodiment 314 shown in FIGS. 64 and 65 includes rectangularintermediate coils 330 and round snap-on end coils 332.

Turning to FIGS. 66 and 67, the embodiment 316 shown therein includescircular intermediate coils 336 with circular snap-on end coils 338. Theembodiment 318 shown in FIGS. 68 and 69 includes elliptical cantedintermediate coils 340 with elliptical end coils 342 which are tapered,as indicated by the arrow 334, and include three locking pointsindicated at 346.

FIGS. 70 and 71 illustrate the embodiment 320 which utilizes ellipticalintermediate coils 350 and elliptical end coils 352 for providingscrew-in engagement, with two locking points located at opposite ends ofthe next-to-the-last leading coils, similar in construction to FIG. 69,but not shown.

Turning now to FIGS. 72-76, there is yet another embodiment 356, inaccordance with the present invention, having intermediate coils 358,360 canted along a centerline 362 and having leading portions 364 andtrailing portions 366, as hereinbefore describe. End coils 370, 372 areeasily distinguished from earlier described embodiments in that thediameter thereof is substantially smaller than the diameter of theintermediate coils 358, 360.

Further, as most clearly shown in FIGS. 73 and 74, the end coils 370extends outwardly from the intermediate coils 364 along the centerlineand the end coil 372 is a female end coil disposed interior to theintermediate coil 360. The embodiment 356 is assembled by threading theend coil 370 into the end coil 372 until the outer portions contact andmatch one another. It should be evident that, because the end coils 370,372 are substantially smaller than the intermediate coils 358, 360,deflection of the intermediate coils 358, 360, as indicated by thearrows 374, depression of the coils 358, 360 in the area of the union ofthe end coils 370, 372 does not affect the load deflectioncharacteristics of the spring assembly 356. FIGS. 75 and 76 offer endviews of the coils 358, 360, 370, 372 and further illustrate the freedomof movement available to the intermediate coils 358, 360.

Another embodiment 380, similar to the embodiment 356, is shown in FIGS.77-79. The coil assembly 380 includes intermediate coils 382, 384, whichmay be elliptical, and end coils 386, 388, as more clearly shown inFIGS. 78 and 79.

FIG. 77 is a top view of the spring apparatus 380 while FIGS. 78 and 79are side views of the spring apparatus 380 prior to assembly. End coils386 extend outwardly from the intermediate coils 382 in a spaced apartmanner, as shown in FIG. 78. End coils 388, disposed within theintermediate coils 384, are sized for accepting the end coils 386 in amanner described in connection with the spring apparatus 356.

Yet another embodiment 392 is shown in FIGS. 80-82, FIG. 80 being a topview at assembly of the spring apparatus 392. Similar to the springapparatus 380, intermediate coils 394, 396 may be elliptical, as well asend coils 398, 400.

However, in the spring apparatus 392 illustrated in FIGS. 80-82, themale end coils 398 are both spaced apart and tapered, the taper beingillustrated with dashed lines 402. Assembly of the spring apparatus 392is in accordance with the assembly procedures describing the springassembly 356.

Still another embodiment 406, in accordance with the present invention,is shown in FIGS. 83-85, with the FIG. 83 being a top view of theassembled spring apparatus 406, and FIG. 84 being a side view of an endcoil 408 prior to assembly. FIG. 85 is a side view of end coil 410 priorto assembly. This embodiment 406 is similar to the spring apparatus 356which includes abutting individual end coils 412, 414 which have asubstantially smaller diameter than intermediate coils 416, 418. The endcoil 408 is distinguished over the end coil 370 (see FIG. 73) in that inaddition to abutting, the end coils 412, 414 are tapered as indicated bythe dashed line 420.

FIG. 86 shows the top view of another embodiment 422 of the presentinvention, which includes intermediate coils 424, 426 congruent with endcoils 428, 430. This spring arrangement 422 is similar to the springarrangement 406 except that the end coils 428 are spaced apart andtapered, as indicated by the dashed line 432.

Yet another embodiment 434, in accordance with the present invention, isillustrated in FIGS. 89a, 89b, 90a, 90b, and 91, FIG. 91 being a cutawayside view of the assembled spring apparatus 434. The spring apparatus434 includes square intermediate coils 436, 438, and is most clearlyshown in FIGS. 89b and 90a around end coils 440, 442.

Turning now to FIG. 92, there is shown yet another embodiment 446 beforeassembly, generally showing intermediate coils 448, 450, which may beelliptical, end coils 452, 454, which are abutting and of substantiallysmaller diameter than the intermediate coils 448, 450, along with aninsert coil 456.

In this embodiment, both the end coils 452, 454 are female and theinsert coil 456 includes male portions 458, 460 sized for insertion intothe end coils 452, 454 with center coils 462 providing a stop. A sideview of the spring apparatus 446 is shown in FIG. 93 prior to assembly,with each of the characterizing angles of the intermediate coils 448,450, end coils 452, 454, as well as the insert coil 456 being indicatedin the figure.

FIG. 94 shows a cutaway spring assembly 446 at maximum deflection whencompressed in the direction of arrows 464 showing the end coils 452, 454in crosssection.

It should be evident from FIG. 94 that the reduced diameter of the endcoils 452, 454, as well as the insert coils 456, enable the intermediatecoils to deflect without bearing against the same and therefore enablingthe intermediate coils a constant load deflection characteristicthroughout a length thereof.

In this embodiment, the end coils 452, 454 may be round, as shown inFIGS. 95 and 96.

Still another embodiment 468 of the present invention is shown in FIGS.97-102, with FIG. 97 being a top view of the spring assembly 468. Thespring assembly 468 is similar to the spring assembly 380 shown in FIGS.77-79 with an important distinguishing feature, as hereinafter setforth.

The spring apparatus 468 includes intermediate coils 470, 472, with endcoils 474, 476, which may be circular, as shown in FIGS. 100 and 101.Specific angular definition of the intermediate coils 470, 472 and endcoils 474, 476 are set forth directly on FIGS. 98 and 99, which are sideviews of the end coils 474, 476, respectively.

In this embodiment 468, the end coils 474 protrude outwardly from theintermediate coils 470 along a centerline 478. In contrast with theassembly 380, as shown in FIGS. 77-79, the end coils 476 comprise femalecoils extending outwardly from the intermediate coils 470 and sized forengagement with male coils 474. The size differential is illustrated inFIGS. 100 and 101.

Because the diameters of the end coils 474, 476 are substantiallysmaller than the diameters of the intermediate coils 470, 472, theintermediate coils may be deflected (as shown in FIG. 102) withoutinterference by the coupling end coils 474, 476. Thus, a constant loaddeflection characteristic of the intermediate coils is maintainedthroughout the length of the spring assembly 468.

Turning now to FIGS. 103-108, there is shown another embodiment 482 ofthe present invention generally including intermediate coils 484, 486and end coils 488, 490. FIG. 103 is a top view of the assembled springassembly 482, while FIGS. 104 and 105 are side views of a separatedassembly, detailing the front angles 494, back angles 496, ashereinbefore described in connection with earlier presented embodimentsof the present invention.

FIGS. 106 and 107 are end views of the end coils 488, 490, respectively,and FIG. 107 most clearly shows a triangular configuration of the endcoil 490 which is a feature of the assembly 482. A dotted line at 492indicates interference locations between the end coils 488, 490 toprovide locking of the end coils 488, 490 together, resulting in thespring assembly 482.

FIG. 108 is a cutaway view of the spring assembly 482 at maximumdeflection under a force indicated by the arrows 496. It can be seenthat in addition to the difference in diameter of the end coils 488, 490and the intermediate coils 484, 486, the triangular shape of the endcoil 490 further enables the compression of the intermediate coils 484,486, without interference from the end coils 488, 490, thereby notinterfering with the load deflection characteristics of the intermediatecoils.

FIGS. 109-115 show still another embodiment 510 of the present inventionwhich is similar to the spring assembly 482, shown in FIGS. 103-108.

As shown assembled is a top view of a spring assembly 510 in FIG. 109,generally including intermediate coils 512, 514, and, as more clearlyshown in FIGS. 110 and 111, end coils 516, 518. Similar to FIGS. 104 and105, FIGS. 110 and 111 show the specific configuration of theintermediate coils 512, 514 and end coils 516, 518.

FIG. 112 is an end view of the round end coil 516, which is similar tothe end coil 488 of the spring assembly 482 with a greater number ofconvolutions.

FIG. 113 illustrates the spring assembly 510 at maximum deflection,showing, as also hereinabove set forth with other embodiments of thepresent invention, deflection of the intermediate coils 512, 514 withoutinterference from the end coils 516, 518.

FIGS. 114 and 115 illustrate the triangular configuration of the endcoil 518, which is similar to the end coil 492 of the spring assembly482, with a greater number of convolutions. Also shown in FIGS. 114 and115 are dotted lines 522, 524 depicting interference locations betweenthe end coils 516, 518 which provide locking of the spring assembly 510,as illustrated in FIGS. 109 and 115.

FIGS. 116-120 show still another embodiment 530 of the presentinvention, generally including a plurality of intermediate coils 532,534 canted along a centerline 536 of the coil spring 530 with each coil532, 534 having a corresponding leading portion 538, 540, disposed atfront angles 542, 554 to normal lines 546, 548 to the centerline 536,and trailing portions 550, 552, disposed at back angles 554, 556 tonormal lines 558, 560 to the centerline 536. End coils 564, 566 arecongruent respectively with the intermediate coils 532, 536 forproviding a joining of the intermediate coils to form the springassembly, as shown in top view in FIG. 116.

Importantly, the end coils 564 include at least one hook coil 570,including an end bent latch portion 572 (see FIGS. 116 and 117) andabutting female coils 574 having a substantially smaller diameter thanintermediate coils 532, 534. Locking is provided when the bent latchportion 572 protrudes through the internal female coils 574, as shown inFIGS. 116 and 121. End views of the end coil 570 are shown in FIG. 119,while the end views of the generally circular end coils 574 are shown inFIG. 120.

A stop is provided upon latching of the two end coils 564, 566 byabutment of the intermediate coils 532, 534, as shown in FIG. 116.

FIG. 121 illustrates the advantage of the present invention by depictingthe spring assembly 530 in cross-section at full deflection in responseto loading in the direction of arrows 580. As illustrated, fulldeflection of the intermediate coils 532, 534 may be achieved withoutinterference from the end coils 564, 566, thereby enabling a constantload deflection characteristic of the intermediate coils 532, 534 overthe continuous length of the assembly 530.

It should be appreciated that all of the hereinabove recited embodimentsmay be filled with an elastomer or plastic, having either a solid or ahollow coil. This configuration is illustrated in FIGS. 122-130 whichshown an elastomer 184 surrounding a spring assembly 586, havingintermediate coils 588, 590 and end coils 592, 594. The purpose of theelastomer is to provide uniform loading, as well as sealing, in additionto providing enhancement of conductivity and electromagnetic shielding,depending upon the consistency of the elastomer exposure of one or morecoils or portions of coils to enhance conductivity and/orelectromagnetic shielding.

FIGS. 123 and 124 show cross-sections taken along the line A--A of FIG.122 for a solid core elastomer 184 (see FIG. 123) and the elastomer 184having a hollow center 598, as shown in FIG. 124. Similarly, FIGS. 125and 126 correspond to view B--B taken from FIG. 122. FIGS. 127 and 128show solid and hollow core elastomer 184 taken along the line C--C inFIG. 122. FIGS. 129 and 130 show solid and hollow core elastomers viewedalong the line D--D of FIG. 122.

Also shown in FIGS. 126 and 128 are contacted area points 602-605,illustrating mechanical linkage between the end coils 592, 594, ashereinbefore described in greater detail.

While the present invention has been hereinabove described in terms ofcanted coils, it should be appreciated that the coils need not becanted. In that regard, FIGS. 131-135 illustrate an embodiment 610, inaccordance with the present invention, in which intermediate coils 612,614 are circular and not canted; and end coils 618, 620 are alsocircular and uncanted. FIGS. 131 and 132 show side and end views,respectively, of the intermediate coils 612 and end coils 618 whereasFIGS. 133 and 134 show side and end views, respectively, of theintermediate coils 614 and end coils 620.

FIG. 135 illustrates the assembly of the end coils 618, 620.

It should also be appreciated that in the embodiments hereinabovedescribed that the end coils may be of the same or differentconfiguration. That is, the elliptical end coil 324 may be used with around end coil 332.

Although there has been hereinabove described a coil spring with endsadapted for coupling without welding, in accordance with the presentinvention, for the purpose of illustrating the manner in which theinvention may be used to advantage, it should be appreciated that theinvention is not limited thereto.

It should be further appreciated that the coupling of spring ends inaccordance with the present invention is particularly suitable forsprings providing bias while at the same time enabling efficientsealing, electromagnetic shielding and/or conductivity.

Accordingly, any and all modifications, variations, or equivalentarrangements which may occur to those skilled in the art, should beconsidered to be within the scope of the present invention as defined inthe appended claims.

What is claimed is:
 1. Spring apparatus comprising:a coiled springhaving two ends and a plurality of intermediate coils canted along acenterline of the coiled spring, each coil having a leading portiondisposed at a front angle to a normal line to one centerline and atrailing portion disposed at a back angle to said normal line; and endcoils congruent with said plurality of intermediate coils, disposed atthe two ends and having back angle means, defining a trailing portion ofat least one end coil, for locking the end coils together, the end coiltrailing portion having a back angle different from the intermediatecoil trailing portion back angle, said end coils having substantiallysmaller diameters than said intermediate coils, one of said end coils isa male end coil extending outwardly from the intermediate coils alongthe centerline and another of said end coils is a female end coilextending outwardly from the intermediate coils along the centerline. 2.The spring apparatus according to claim 1 wherein said male end coilcomprises abutting coils.
 3. The spring apparatus according to claim 2wherein the abutting coils are tapered.
 4. The spring apparatusaccording to claim 3 wherein said female end coil comprises abuttingcoils.
 5. The spring apparatus according to claim 1 wherein saidintermediate coils are elliptical.
 6. The spring apparatus according toclaim 1 wherein said intermediate coils are elliptical and the male andfemale end coils are round.
 7. The spring apparatus according to claim 1wherein said intermediate coils are rectangular.
 8. The spring apparatusaccording to claim 1 wherein said intermediate coils are rectangular andthe male and female end coils are round.
 9. The spring apparatusaccording to claim 1 wherein said male end coil comprises spaced apartcoils.
 10. The spring apparatus according to claim 9 wherein the spacedapart coils are tapered.
 11. The spring apparatus according to claim 10wherein said female end coil comprises spaced apart coils.
 12. Thespring apparatus according to claim 10 wherein said intermediate coilsare elliptical.
 13. The spring apparatus according to claim 10 whereinsaid intermediate coils are elliptical and the male and female end coilsare round.
 14. The spring apparatus according to claim 11 wherein saidintermediate coils are rectangular.
 15. The spring apparatus accordingto claim 11 wherein said intermediate coils are rectangular and the maleand female end coils are round.
 16. The spring apparatus according toclaim 11 wherein said intermediate coils are elliptical and the male endcoils are triangular.
 17. The spring apparatus according to claim 16wherein the female end coils are round.